<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>CSS z-index Property</title>
<style>
<!--

#a,#b{width:100px;height:100px;color:#FFF;}
#a{background:#C00;margin:0 0 -100px 50px;}
#b{background:#00C;}

-->
</style>
</head>
<body>

<div id="a" style="position:fixed;">A</div>
<div id="b">B</div>

</body>
</html>